Someone is mysteriously stealing from Kanundda Council's new state-of-the-art electronic safes. When a particularly sensitive letter disappears from the safe of the general manager, Jan Campbell-Jones, Jan calls in Edgar Hodgkiss to solve the problem. From a few random observations Hodgkiss finds a remarkable solution that exposes a network of ingenious criminals.
Hodgkiss and his daughter Esme Burke receive a call for help from an elderly lady, once a friend of the family. But when they arrive things are not as they expected. Hodgkiss' suspicions are aroused by the appearance of the man who claims to be a relative of the timid, frightened woman. Soon he proves the man is not who he claims to be and puts an end to his attempts to steal a collection of valuable clocks.
When visiting a friend Hodgkiss notices the extraordinary behaviour of a man on the balcony of the flat above where his friend lives. Later, when a body is found in the flat Hodgkiss and Donald lock horns once more over the question, was it suicide or murder, this time with a surprising climax.